A5016340836- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Planetary Science and Exploration
- Meteorological Phenomena and Simulations
- Methane Hydrates and Related Phenomena
- Spacecraft and Cryogenic Technologies
- Cryospheric studies and observations
- Space Exploration and Technology
- Paleontology and Stratigraphy of Fossils
- Scientific Research and Discoveries
- Stellar, planetary, and galactic studies
Laboratoire de Météorologie Dynamique
2022-2024
Sorbonne Université
2022-2024
École Polytechnique
2022-2024
École Normale Supérieure - PSL
2024
Laboratoire atmosphères, milieux, observations spatiales
2022-2024
Centre National de la Recherche Scientifique
2024
Institut Pierre-Simon Laplace
2023-2024
Université Paris Sciences et Lettres
2024
While small Neptune-like planets are among the most abundant exoplanets, our understanding of their atmospheric structure and dynamics remains sparse. In particular, many unknowns remain regarding way moist convection works in these atmospheres, where condensable species heavier than non-condensable background gas. it has been predicted that could cease above some threshold abundance species, this prediction is based on simple linear analysis relies strong assumptions saturation atmosphere....
Neptune's tropospheric winds are among the most intense in Solar System, but dynamical mechanisms that produce them remain uncertain. Measuring wind speeds at different pressure levels may help understand atmospheric dynamics of planet. The goal this work is to directly measure stratosphere with ALMA Doppler spectroscopy. We derived lineshift maps Neptune CO(3-2) and HCN(4-3) lines 345.8 GHz ($\lambda$~0.87 mm) 354.5 (0.85 mm), respectively. For that, we used spectra obtained 2016 recorded a...
While small, Neptune-like planets are among the most abundant exoplanets, our understanding of their atmospheric structure and dynamics remains sparse. In particular, many unknowns remain on way moist convection works in these atmospheres where condensable species heavier than non-condensable background gas. it has been predicted that could shut-down above some threshold abundance species, this prediction is based simple linear analysis relies strong assumptions saturation atmosphere. To...
Context . The observations made during the Voyager 2 flyby have shown that stratosphere of Uranus and Neptune are warmer than expected by previous models. In addition, no seasonal variability thermal structure has been observed on since era significant subseasonal variations revealed Neptune. Aims this paper, we evaluate different realistic heat sources can induce sufficient heating to warm atmosphere these planets estimate effects structure. Methods radiative-convective model developed...
Flyby of Uranus and Neptune by Voyager 2 in 1986 1989 have shown intense zonal circulation unexpected meteorological activity. Characterized a prograde jet at mid-latitude each hemisphere retrograde centred on the equator, structure wind is similar these two planets despite very different seasonal radiative forcing. Understanding atmospheric gas ice giant planets, with comparative planetology aspects that could be relevant to exoplanet community one major current challenges physics planetary...
Uranus and Neptune have atmospheres dominated by molecular hydrogen helium. In the upper troposphere, methane is third main molecule condenses, yielding a vertical gradient in CH4. This condensable species being heavier than H2 He, resulting change mean weight due to condensation comes as factor countering dry moist convection. As observations also show latitudinal variations abundance, one can expect different gradients from latitude another. this paper, we investigate impact of on...
The observations made during the Voyager 2 flyby have shown that stratosphere of Uranus and Neptune are warmer than expected by previous models. In addition, no seasonal variability thermal structure has been observed on since era significant subseasonal variations revealed Neptune. this paper, we evaluate different realistic heat sources can induce sufficient heating to warm atmosphere these planets estimate effects structure. radiative-convective model developed Laboratoire de...
Remote-sensing monitoring of Neptune has revealed temperature variations in the atmosphere planet [1,2,3,4] since flyby Voyager 2 [5]. These are not uniform latitude or pressure level, with Southern polar region and stratospheric levels showing higher activity. In this work we present analysis ALMA observations at CO(3-2) line 345.8GHz. measurements were recorded 2016 a spatial resolution about 0.37” on Neptune’s 2.24” disk. We find that spectral range is...
Uranus and Neptune, also known as the ice giants of solar system, have received less attention from scientific community compared to other planets. Their atmospheric dynamics are very different those gas giants, due their size, composition, rotation period greater distance Sun. For example, Neptune has strongest zonal wind observed in similar mid-latitude jets despite its seasonal forcing absence internal heat. In addition, study will provide new insights into planet formation evolution,...
Located at an average distance of 19 AU and 30 respectively from the sun, Uranus Neptune are mysterious hard-to-reach worlds. These two planets characterized by low sunshine long orbital periods very marked seasonal variations (especially for Uranus). Today, Voyager 2 is only probe to have made a flyby these it has revealed that cold worlds intense atmospheric circulation [1,2]. Since then, other zonal wind measurements using cloud tracking been carried out with aid Hubble Space Telescope...
Neptune's tropospheric winds are among the most intense in Solar System, but dynamical mechanisms that produce them remain uncertain. Measuring wind speeds at different pressure levels may help understand atmospheric dynamics of planet. The goal this work is to directly measure stratosphere with ALMA Doppler spectroscopy. We derived lineshift maps Neptune CO(3-2) and HCN(4-3) lines 345.8 GHz ($λ$~0.87 mm) 354.5 (0.85 mm), respectively. For that, we used spectra obtained 2016 recorded a...
ContextOne-dimensional modelling efforts for icy giant atmospheres have been performed in the past, from pioneering works to more recent comprehensive studies [2]. Circulation patterns troposphere and stratosphere inferred visible, infrared, microwave observations models discussed [3], but few fully three-dimensional of Ice Giants ever presented.Among differences between these are estimated radiative time constants consequences atmospheric circulation on Uranus Neptune.  For...
Uranus and Neptune’s atmospheres are active worlds, with vigorous meteorological activity strong zonal winds occurring despite small absorbed solar radiation internal heat fluxes. A few 3-D General Circulation Models (GCM) of their exist in the literature, focusing mostly on understanding jet structure [1,2] or evolution large disturbances [3,4].Building a complete realistic GCM is challenging task, given long orbital radiative timescales involved, along rather high spatial...
<p>Uranus and Neptune have a tropopause, stratosphere thermosphere inexplicably too hot. This problem is called "Energy Crisis" [1,2]. Radio occultation measurements [3,4] UV stellar solar [5,6] by Voyager 2 revealed that their reach values of 150 K 800 K. Globally-averaged temperature observations [7,8] also shown warmer than expected. Current radiative equilibrium models can’t explain the observed temperatures [9,10], one or several unknown...